Abrasive tool



Aug. 29, 1939. L J. KAUFMAN ET AL ABRASIVE TOOL Filed June 15, 1935g/vvvw/z/s L-J-KEm rnan E-H-E em haK 3/ W MID/0W6 Patented Aug. 29, 1939UNITED STATES PATENT OFFICE ABRASIVE TOOL Application June 15, 1935,Serial No. 26,810

1 Claim.

This invention relates to abrasive tools, and more particularly to toolsfor refinishing valve seats of various contours.

In the refinishing of valve seats, at the present time, it is customaryto utilize a cutting tool, or an abrasive tool, in which theabrasive-coated material is pre-formed or shaped to the tool and contourof the valve seat, or work to be finished.

Grinding or cutting tools are expensive, require accurate guides andpilots, and when dull leave the work ridged and marked, in addition torequiring highly skilled labor. In instances where abrasive tools areutilized, pre-forming of the abrasive material addsmaterially to itscost, and it is necessary to carry a great many shapes and sizes instock, and the pre-formed abrasive cup or element tends to loosen up orWrinkle during rotation of the tool.

The present invention has primarily for its object to overcome theforegoing objections by the provision of an exceedingly simple,inexpensive and efiicient abrasive tool adapted to utilize a normallyfiat disc or sheet of flexible, abrasivecoated material, such as clothand the like, which may be readily replaced as often as is needed atminimum expense.

Incidental to the foregoing, a more specific object resides in theprovision of a tool of the foregoing character, utilizing chucks ofsubstantially conical form, and flexible, abrasive-coated discs orsheets: adapted to be readily clamped on and conformed to the chuck andwork, thus insuring a smooth, accurate finish.

A still further object of our invention is the provision of a spiderhaving radially projecting. inclined arms adapted to engage a normallyflat flexible sheet of abrasive material for forming the material on thehead of the tool with folds in the material, whereby the accurateshaping of the material is insured, and whereby slipping or wrinkling ofthe material when the tool is in use is eliminated.

With the above and other objects in View, which will appear as thedescription proceeds, the invention resides in the novel construction,combination and arrangement of parts, substantially as hereinafterdescribed and more particularly defined by the appended claim, it beingunderstood that such changes in the precise embodiment of the hereindisclosed invention may .be made as come within the scope of the claim.

In the accompanying drawing is illustrated one complete example of thephysical embodiment of the present invention constructed according tothe best mode so far devised for the practical ap plication of theprinciples thereof.

In the drawing:

Figure l is a vertical section through one preferred form of ourimproved tool designed for finishing valve seats of internal combustionengines and the like, a fragment of the valve seat being shown insection.

Figure 2 is a detail illustrating a flexible connection provided for thetool stem, parts being shown broken away and in section.

-Figure 3 is a bottom plan section taken on the line 3-3 .of Figure 1.

Figure 4 is a plan of the blank forming the abrasive disc utilized withour improved tool,

Referring to the drawing in detail, wherein similar reference charactersdesignate corresponding parts throughout the several views, the

letter A generally indicates our improved tool, which embodies a solidcylindrical shank 5, having a collar 6 knurled .or otherwise securedthereon to form a shoulder. The upper end of the shank 5 is providedwith threads 1 for the reception of a coupling member or nut 8, whichcooperates with the collar 6 to clamp the operating head 9 thereon. Thehead is removable, either for replacement of a different shaped head orrenewal of the abrasive disc or sheet l0, as will be hereinafterdescribed.

The working head 9 illustrated is provided with a tapered working faceof substantially forty-five degrees, and interrupted at a plurality ofspaced points by radial grooves I I.

Obviously, in a head of any substantial diameter provided with a workingface formed at arelatively steep angle, it is impossible to make a flatflexible disc or sheet to conform thereto without bunching, which wouldbe detrimental to both the abrasive sheet and the valve seat. Therefore,in order to insure a snug, smooth fit of the abrasive disc or sheet overthe inclined working face of the head 9, a spider I2 is provided. Thespider l2 includes a flat apertured hub I3, and radially extendinginclined arms M. The hub I3 of the spider I2 is slipped on the shank inengagement with the collar 6, and the radial arms M are alined andreceived within the grooves II in the head 9, as best shown in Figure 1.

In actual practice, it is preferred to form the spider of resilientmaterial, in order that the arms l4 may exert a slight tension upon thefolds of the disc Ill forced into the grooves II.

In grinding the valve seats of internal combustion engines and the like,accuracy is desirable, and, therefore, in work of this character theshank 5, in addition to serving to hold the head and abrasive disc I0 inassembled relation, also acts as a pilot, in that it is fitted into theusual valve stem guide l5 of the engine. Thus, the shank 5 serves toaccurately aline the working face of the head with the valve seat l6.

Inasmuch as the tool A is then guided, it is desirable to provide aflexible connection between the same and the operating shank 20.Therefore, the lower end of the operating shank 20 is provided with aspherical head 2|, which fits into a recess ll formed in the couplingmember or nut 8. The transverse slot 22 in the spherical head 2!receives a pin l8 carried by the coupling member or nut 8. Thus, in theevent of disalinement, all relative movement between the stem 20 and thetool A is readily compensated for, and will, therefore, not aifect theaccuracy of the finishing operation.

In Figure 4 the manner in which the folds occur in the abrasive disc l0,when the same is clamped to the head 9 by the spider I2, is illustratedin dotted lines. Obviously, the tightening of the coupling member or nut8 on the stem or shank 5 will clamp the head 9, the spider I2, and theabrasive disc or sheet [0 firmly together.

Particular attention is invited to the fact that the arms i l of thespider form the folds in the abrasive disc or sheet H), and prevent thebunching, wrinkling, or slipping of the abrasive sheet or disc ill onthe head.

From the foregoing description considered in conjunction with theaccompanying drawing, it will be readily seen that a comparativelyinexpensive and highly efficient tool has been provided, which willmaterially reduce the cost of grinding or refinishing valve seats,inasmuch as the same is accomplished by the use of inexpensive, thin,flat abrasive discs or sheets requiring no special shapes, and becauseof their relatively low costs, permitting frequent replacement.

Further, should the operator run out of discs supplied for the tools,the same can be readily formed out of ordinary abrasive cloth or paper,without the delay incident to obtaining a new supply.

A further advantage resulting from the structure is that the discsthemselves can be shifted on the head or chuck 9 upon the loosening ofthe clamping means, so that the. unused surfaces (the folds) can bepresented for use, after one portion of the discs has become worn.

Changes in details may be made without departing from the spirit or thescope of our invention, but what we claim as new is:

In a valve seat grinding tool, a rotatable body, an abrasive supportinghead on one end of said body and having a side wall surface tapered atan angle corresponding substantially to the angle body and extendinginto said indentations and constructed and arranged to press theabrading element inwardly into said head grooves to draw and hold saidelement evenly and tautly upon said head, and means carried by said bodyand operable to move and hold said first means within said indentationsand also adapted to detachably secure said first means and abradingelement in place upon said head.

LEONARD J. KAUFMAN. CHARLES H. SHEMCI-IAK.

